Constituents of SH1, a Novel Lipid-Containing Virus Infecting the Halophilic Euryarchaeon Haloarcula hispanica

Abstract

Recent studies have indicated that a number of bacterial and eukaryotic viruses that share a common architectural principle are related, leading to the proposal of an early common ancestor. A prediction of this model would be the discovery of similar viruses that infect archaeal hosts. Our main interest lies in icosahedral double-stranded DNA (dsDNA) viruses with an internal membrane, and we now extend our studies to include viruses infecting archaeal hosts. While the number of sequenced archaeal viruses is increasing, very little sequence similarity has been detected between bacterial and eukaryotic viruses. In this investigation we rigorously show that SH1, an icosahedral dsDNA virus infecting Haloarcula hispanica, possesses lipid structural components that are selectively acquired from the host pool. We also determined the sequence of the 31-kb SH1 genome and positively identified genes for 11 structural proteins, with putative identification of three additional proteins. The SH1 genome is unique and, except for a few open reading frames, shows no detectable similarity to other published sequences, but the overall structure of the SH1 virion and its linear genome with inverted terminal repeats is reminiscent of lipid-containing dsDNA bacteriophages like PRD1.

Global morphological analysis of marine viruses shows minimal regional variation and dominance of non-tailed viruses

“…This is likely because physico-chemical variables in the oceanic samples did not approach the 'extreme' conditions from which these exceptional morphotypes have been isolated. However, there are non-marine archaeal viral isolates with icosahedral non-tailed morphology (Bamford et al, 2005;Atanasova et al, 2012;Jaakkola et al, 2012) and further exploration of marine archaeal virushost systems may yield more examples.…”

The bioactivity of human bone morphogenetic protein-15 is sensitive to C-terminal modification: Characterization of the purified untagged processed mature region

“…Flow rate was 50µl/min and detection at 214nm. For in-gel digestion the P16 and P17 protein bands from SDS-PAGE (Laemmli 1970) were separately in-gel digested with trypsin (Bamford et al 2005) and the resulting peptides subjected to peptide mass fingerprint analysis by MALDI-TOF mass spectrometry.…”

Gammasphaerolipovirus, a newly proposed bacteriophage genus, unifies viruses of halophilic archaea and thermophilic bacteria within the novel family Sphaerolipoviridae

“…It has an icosahedral capsid with spikes on the five-fold vertices, an inner lipid membrane, and no tail. The linear dsDNA genome has inverted terminal repeats and proteins attached to the termini [7,43]. However, closer analysis of the 31-kb genome and the capsid structure revealed that SH1 differs markedly from members of the Tectiviridae.…”

“…In 2003, a spherical halovirus, SH1, infecting the euryarchaeon Haloarcula hispanica was isolated from Lake Serpentine in Western Australia [13] and characterized in detail during the next few years [7,23,29,[42][43][44]. The particle morphology and genome structure of this virus resemble those of bacteriophages belonging to the family Tectiviridae [2].…”